WO2000032903A1 - Supply system and method for changing wires in a riser tensioner system - Google Patents

Supply system and method for changing wires in a riser tensioner system Download PDF

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Publication number
WO2000032903A1
WO2000032903A1 PCT/NO1999/000349 NO9900349W WO0032903A1 WO 2000032903 A1 WO2000032903 A1 WO 2000032903A1 NO 9900349 W NO9900349 W NO 9900349W WO 0032903 A1 WO0032903 A1 WO 0032903A1
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WO
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Prior art keywords
wire
cylinder
riser
riser tensioner
wedging means
Prior art date
Application number
PCT/NO1999/000349
Other languages
French (fr)
Inventor
Matheus Christensen
Øystein CHRISTENSEN
Original Assignee
Future Productions As
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Future Productions As filed Critical Future Productions As
Priority to AU14177/00A priority Critical patent/AU1417700A/en
Publication of WO2000032903A1 publication Critical patent/WO2000032903A1/en

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B19/00—Handling rods, casings, tubes or the like outside the borehole, e.g. in the derrick; Apparatus for feeding the rods or cables
    • E21B19/002—Handling rods, casings, tubes or the like outside the borehole, e.g. in the derrick; Apparatus for feeding the rods or cables specially adapted for underwater drilling

Definitions

  • the present invention relates to a system for changing of a worn or presumably worn wire in a riser tensioner system 7 on the deck of a platform carrying the upper load ring 2 on a platform offshore.
  • This is outlined in figure 1.
  • the task of the riser 1 is to carry a drill string and keep the drilling fluid therein away from the seawater and the air.
  • the drilling fluid has at least five functions: cooling of drill string 3 and reducing the friction against the borehole wall during drilling, and transporting of cuttings and sand out of the borehole 4, and to form a back pressure against the litostatic and hydrostatic pressure in the borehole wall 6, and also to form a chemically compatible environment in the borehole in relation to the geological formations.
  • the purpose of keeping the drilling fluid in the riser is partly to lubricate the drill string 3 so as to reduce the friction against the riser wall, but mainly to utilize all or part of the length above the sea bed to form a hydrostatic pressure at the liquid column from the drill bit to the top level of the drilling fluid, usually RKB.
  • FIG. 2 shows load-carrying wires 10a,b,..,h, usually a number of 8, but less or more than 8 may be arranged between the platform deck 5 and the load ring 2 of the riser. Because of heave and hunting in the platform in relation to the sea bed, relative movements occur between the riser and the deck 5 of the platform. This movement is compensated by means of riser tensioners 7a,b,..,h which automatically control the length of each wire 10a,b,..,h as the platform deck 5 moves in relation to the riser 1, so as to keep an even vertical tension in the load ring 2 on riser 1. The adjustment of the length of the wires 10a,b, .. ,h takes place by means of a hydraulic piston 71 carrying an upper tackle block 75.
  • a hydraulic piston 71 carrying an upper tackle block 75.
  • This hydraulic piston 71 runs in a corresponding hydraulic cylinder 73 supported on a lower tackle block 74 .
  • the active part of the wire 10a,b, . . ,h being fastened to the platform deck is attached by means of a clamp 75 at the lower tackle block 74, which directly or indirectly is attached to the platform deck 5. Because changing of wire is required before it is damaged due to wear and tear, supply reels 11 with "fresh" unused wire 10a 1 ,b' , .. ,h' are arranged for, only being divided from the active wire by the clamp 76.
  • New wire 10a 1 is paid out from supply reel 11 while the crew pull old wire 10a through the ring 21 on the load ring 2 until the desired length of the wire 10a is replaced by new wire 10a' .
  • the crew attach the clamp 76 to the new attachment portion of the wire 10a retaining the wire 10a and divides between the active part of the wire 10b and the remaining length of wire 10b on the supply reel 11 .
  • This is an uncomplicated operation.
  • the crew on the load ring attach the new "end" of the new portion of the wire 10a (the old portion of the wire 10a has not yet been cut off) by means of hand tools in the ring 21 on load ring 2.
  • the crew move the wire 10a over to the riser and mount the clamp on load ring 2.
  • the riser tensioner 7 is returned to a state of normal operation.
  • the steps 1-7 are repeated for each wire 10a,J,..,h to be replaced or shifted.
  • the invention relates to a riser tensioner system
  • a riser tensioner system comprising a riser tensioner with a hydraulic cylinder/- piston including a tackle block system arranged to carry a riser in wires which usually are fastened to a load ring at the top of the riser, and at least one passive supply reel with new wires in continuation of the wires.
  • Novel features of the invention are a cylinder arranged for being run through of a wire, where one end of the cylinder has a fastening boss attached to the load ring and where the cylinder comprises a releasable and shiftable wedging means with wire wedges and lock rings for retaining the wire, a wedge slider being firstly arranged for shifting the wedging means including the wire from a starting point, towards the direction of the load ring, arranged for paying out one (used/worn) end of the wire, and secondly arranged for shifting the wedging means in the opposite direction from the load ring back to the starting position for a new retaining of the wire, locking pawls arranged for temporary retaining of the wire) while the wedging means is shifted back to the starting positon, and a wire cutter in the cylinder arranged for cutting off the paid-out end of the used wire.
  • a lever with a wire cutter is arranged for cutting off the paid-out end of the used wire.
  • Figure la shows a drilling platform with a riser connected to an exhaust valve in a well in the sea bed.
  • Figure lb shows a simplified section of the cellar deck and the opening to the riser, together with the riser tensioner and unhooked wire.
  • Figure 2a shows a partial perspective view of a riser tensioner in connection with a section of a load ring 2 on a telescopic pipe on a riser.
  • Figure 2b shows a simplified section of the invention comprising a cylinder arranged for connecting the wire to the load ring on the riser, and a gripping lever for taking care of used paid-out wire.
  • Figures 3a and 3b show a section of the embodiment of the cylinder in the invention.
  • Figure 3c shows an embodiment of the invention wherein a cutting means for paid-out wire are located within the cylinder.
  • Figure 3d illustrates an embodiment of the invention wherein a wedging means are made of a shape memory metal or an alloy having this property (SMA) .
  • Figure la shows a drilling platform with a riser 1 connected to an exhaust valve in a well in geologic formations in the sea bed.
  • Figure lb sketches scematically that the wire 10a, b, . . ,h is taken on to the cellar deck, the riser tensioner 7 and the supply reel 11.
  • Figure 2a describes a riser tensioner system comprising a riser tensioner 7 with a hydraulic cylinder/piston 71 , 73 with a tackle block system 74,75 arranged for carrying a riser 1 in wires 10a,b, . . ,h .
  • the wires 10a,b, . . ,h are usually fastened to a load ring 2 near the top of the riser 1.
  • at least one passive supply reel 11 with new wire 10a ' ,b ' , .. ,h ' are located n the cellar deck in continuation of the wires 10a,b, . . , .
  • Figure 2b shows in a simplified form an embodiment of the invention comprising a cylinder 8 which connects the wire 10a,b, . . ,h to the load ring 2.
  • Figure 3a shows some of the components being comprised of an embodiment of the invention.
  • a tubular cylinder 8 is arranged for being run through by the wire 10a, b, . . ,h .
  • One end of the cylinder 8 has a fastening boss 80 which is attached to the load ring 2.
  • one cylinder for each wire 10a,J,..,h to retain the riser 1 is arranged, usually six to eight wires 10a,b, . . ,h .
  • the cylinder 8 comprises a releasable and shiftable wedging means 9 with wire wedges 9 ' and lock ring 9" for retaining of the wire 10a,b, . . ,h .
  • a wedge slider 14 is arranged for shifting the wedging means 9 with the wire 10a,b, . . ,h from a starting position furthest away from the load ring 2.
  • the wedge slider 14 shifts the wedging means 9 in the direction towards the load ring 2 when the wire wedges 9 ' have got a grip about the wire 10a.
  • one (used/worn) end of the wire 10a, b, . . ,h is paid out near the load ring 2.
  • the wedging means 9 is then shifted by the wedge slider 14 in the opposite direction of the load ring 2 back to the starting position.
  • the wedging means 9 is in position for a new gripping and retaining of the wire 10a, b, .. ,h .
  • the wedging means 9 e.g. the wire wedge 9 '
  • the wire wedge 9 ' be made of a shape memory metal or an alloy having this property (SMA) .
  • SMA shape memory metal or an alloy having this property
  • Such metals and alloys have the feature that after deformation, they have the ability to "remember” and retrieve their initial shape through heating.
  • the deformation should not exceed a fraction of one percent before the deformation becomes plastic, that is, irreversible.
  • SMA the limit for plastic deformation is substantially increased if the strain of the body is below 10% and takes place below a certain temperature.
  • the wire wedge 9' may for example have the shape of a cylinder. The cylinder expands or shrinks about the wire at temperatures as mentioned above. This embodiment of the invention is illustrated in figure 3d.
  • Locking pawls 18 located in the cylinder 8 are arranged for unidirectionally being run through by the wire and temporary retaining of the wire 10a,Jb,..,2 ⁇ while the wedging means 9 is shifted back to the starting position.
  • Figur 3b shows how hydraulic pressure may be used for activating the wire wedges vaierkilene 9 ' and lock ring 5", together with the wedge slider 14 and, if any, the locking pawls 18 .
  • the locking pawls 18 are merely spring-loaded and tow against the wire in one direction, and is tightened against the wire if the wire is pulled in the opposite direction.
  • a hydraulically driven wire cutter 16 is arranged within the cylinder 8. This wire cutter is arranged for cuttin off the paid-out end of the used wire 10a,b, . . ,h by means of a hydraulic piston urging a wedge- shaped cutting edge 17 through the wire 10a.
  • This is required in order to take care of the cut wire 10a,J,..,h to prevent falling wire cutting against the riser and the exhaust valve (large dimensions of the wire are here in question) .
  • the lever 20 may also be provided with the wire cutter 16 , arranged for controlling the wire cutter 16 to engagement with the paid-out end of the paid-out wire 10a, b, ..
  • changing of wire 10a,Jb,..,h takes place mechanically. This takes place in the following manner: a) A riser tensioner is taken out of normal operation.
  • the pressure in cylinder 73 of the riser tensioner is reduced so as to release the tension in a wire (e.g.
  • Locking pawls 18 retain the wire 10a while the wedging means 9 is shifted back to the starting positon I. Through this operation, new wire 10a' is drawn from the supply reel 11 . This step is repeated until the desired length of wire 10a is replaced by new wire 10a' . d) Clamp 76 is again attached to a new position on the wire 10a, thereby dividing between the active part of the wire 10a in the riser tensioner, and the remaining length of wire 10b on the supply reel 11. e) Wire wedges 9 ' are locked about the wire 10a in position I by means of the lock ring 9 " .
  • hydraulically driven components will be present in the cylinder 8 and the surrounding components, but an embodiment of the invention with electrical components is also possible.
  • the system may be operated by an operator in some distance, thereby substancially reducing the danger of injuries to the operator while at the same time the operation may be carried out more quickly and safely.

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  • Engineering & Computer Science (AREA)
  • Geology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Mining & Mineral Resources (AREA)
  • Physics & Mathematics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Earth Drilling (AREA)
  • Cable Accessories (AREA)
  • Laying Of Electric Cables Or Lines Outside (AREA)
  • Air Bags (AREA)

Abstract

This invention relates to a riser tensioner system comprising a riser tensioner with a hydraulic cylinder/piston including a tackle block system adapted to carry a riser in wires which usually are fastened to a load ring at the top of the riser, and at least one passive supply reel with new wires in continuation of the wires. The novel features of the invention are a cylinder adapted for the running through of a wire, where one end of the cylinder has a fastening boss attached to the load ring and where the cylinder comprises a releasable and shiftable wedging means with wire wedges and lock ring for retaining the wire, a wedge slider being firstly adapted to shift the wedging means including the wire from a starting point, towards the direction of the load ring, adapted for paying out one (used/worn) end of the wire, and secondly adapted for shifting the wedging means in the opposite direction from the load ring back to the starting position for a new retaining of the wire, locking pawls adapted for temporary retaining the wire while the wedging means is shifted back to the starting position, and a wire cutter in the cylinder adapted to cut off the supplied end of the used wire.

Description

SUPPLY SYSTEM AND METHOD FOR CHANGING WIRES IN A RISER TENSIONER SYSTEM.
Background of the invention
The present invention relates to a system for changing of a worn or presumably worn wire in a riser tensioner system 7 on the deck of a platform carrying the upper load ring 2 on a platform offshore. This is outlined in figure 1. The task of the riser 1 is to carry a drill string and keep the drilling fluid therein away from the seawater and the air. The drilling fluid has at least five functions: cooling of drill string 3 and reducing the friction against the borehole wall during drilling, and transporting of cuttings and sand out of the borehole 4, and to form a back pressure against the litostatic and hydrostatic pressure in the borehole wall 6, and also to form a chemically compatible environment in the borehole in relation to the geological formations. The purpose of keeping the drilling fluid in the riser is partly to lubricate the drill string 3 so as to reduce the friction against the riser wall, but mainly to utilize all or part of the length above the sea bed to form a hydrostatic pressure at the liquid column from the drill bit to the top level of the drilling fluid, usually RKB.
Field of the invention
Figure 2 shows load-carrying wires 10a,b,..,h, usually a number of 8, but less or more than 8 may be arranged between the platform deck 5 and the load ring 2 of the riser. Because of heave and hunting in the platform in relation to the sea bed, relative movements occur between the riser and the deck 5 of the platform. This movement is compensated by means of riser tensioners 7a,b,..,h which automatically control the length of each wire 10a,b,..,h as the platform deck 5 moves in relation to the riser 1, so as to keep an even vertical tension in the load ring 2 on riser 1. The adjustment of the length of the wires 10a,b, .. ,h takes place by means of a hydraulic piston 71 carrying an upper tackle block 75. This hydraulic piston 71 runs in a corresponding hydraulic cylinder 73 supported on a lower tackle block 74 . The active part of the wire 10a,b, . . ,h being fastened to the platform deck is attached by means of a clamp 75 at the lower tackle block 74, which directly or indirectly is attached to the platform deck 5. Because changing of wire is required before it is damaged due to wear and tear, supply reels 11 with "fresh" unused wire 10a1 ,b' , .. ,h' are arranged for, only being divided from the active wire by the clamp 76. The wire 10a.,b, . . ,h is then threaded from the clamp 76 via the upper tackle block 75 back via the lower tackle block 74 at least once, and in one particular embodiment twice, so that the wire 10a,Jb, .. ,h runs four times in the riser tensioner before it leaves via a pulley 12 to the load ring. Thus a movement upwards a length x of the hydraulic piston 71 will involve a length 4x of the wire 10a. The riser tensioner is controlled by a data system registrating the heave movement of the platform or the relative movement between the load ring 2 and the platformdeck 5.
Problem to be solved When wires 10a.,b, . . , have travelled in the riser tensioners 7 and over the pulleys 12 during a couple of months, and have been bent and worn for each single passing sea wave longer than a certain wavelength, wear and tear occur in the wires. If the wires 10a,b, . . ,h are broken, the hydraulic piston 71 will strike out due to hydraulic forces, even if a speed control valve exists for this purpose. If there is unsufficient amounts of oil in the hydraulic system, the riser tensioner 7 may be destroyed. This is dangerous to the crew working nearby. The costs for materials, logistics and manhours when changing a riser tensioner are substantial.
According to the present prior art before filing this patent application, changing of a wire 10a,J,..,h takes place manually. This takes place in the following manner: 1) A riser tensioner is taken out of normal operational mode. The pressure in the cylinder 73 of riser tensioner is reduced so as to release the tension in a wire (e.g. 10a) of the wires 10a,Jb,..,h. 2) The crew release the fastening clamps of the wire 10a from load ring 2 on riser 1 and bring the fastening clamps of the wire 10a on to the cellar deck. This is a dangerous operation for the crew due to steady movement between the load ring 2 and the platform deck 5, and injuries to crew is not unusual.
3) When the crew have released the wire 10a from a ring 21 on the load ring 2, the clamp 76 retaining the wire 10a is released and divides between the active part of the wire 10a and the paid-out part of the wire 10a1 on the supply reel 11 .
4) New wire 10a1 is paid out from supply reel 11 while the crew pull old wire 10a through the ring 21 on the load ring 2 until the desired length of the wire 10a is replaced by new wire 10a' .
5) The crew attach the clamp 76 to the new attachment portion of the wire 10a retaining the wire 10a and divides between the active part of the wire 10b and the remaining length of wire 10b on the supply reel 11 . This is an uncomplicated operation. The crew on the load ring attach the new "end" of the new portion of the wire 10a (the old portion of the wire 10a has not yet been cut off) by means of hand tools in the ring 21 on load ring 2. The crew move the wire 10a over to the riser and mount the clamp on load ring 2.
6) The pressure in the cylinder 73 of the riser tensioner is increased until the new portion of the wire between the clamp 76 and the ring 21 is tensioned.
7) The riser tensioner 7 is returned to a state of normal operation.
The steps 1-7 are repeated for each wire 10a,J,..,h to be replaced or shifted.
Description fo prior art in the field
Patent specifications of wire tensioning apparatuses exist, describing the use thereof among other things for shaft lifts in mines. DE 39 36 845: "Klemm- und Zugvorricht- ung zum taktweisen Herausziehen der Fδrderseile wahlweise eines der Trume einer Bergbau-Schachtfδrderanlage" describes an apparatus gripping about a number of cables in a mine lift for reducing to tighten untensioned cables.
Summary of the invention
The invention relates to a riser tensioner system comprising a riser tensioner with a hydraulic cylinder/- piston including a tackle block system arranged to carry a riser in wires which usually are fastened to a load ring at the top of the riser, and at least one passive supply reel with new wires in continuation of the wires. Novel features of the invention are a cylinder arranged for being run through of a wire, where one end of the cylinder has a fastening boss attached to the load ring and where the cylinder comprises a releasable and shiftable wedging means with wire wedges and lock rings for retaining the wire, a wedge slider being firstly arranged for shifting the wedging means including the wire from a starting point, towards the direction of the load ring, arranged for paying out one (used/worn) end of the wire, and secondly arranged for shifting the wedging means in the opposite direction from the load ring back to the starting position for a new retaining of the wire, locking pawls arranged for temporary retaining of the wire) while the wedging means is shifted back to the starting positon, and a wire cutter in the cylinder arranged for cutting off the paid-out end of the used wire.
In an alternative embodiment of the invention, a lever with a wire cutter is arranged for cutting off the paid-out end of the used wire.
Description of the drawings
Figure la shows a drilling platform with a riser connected to an exhaust valve in a well in the sea bed.
Figure lb shows a simplified section of the cellar deck and the opening to the riser, together with the riser tensioner and unhooked wire.
Figure 2a shows a partial perspective view of a riser tensioner in connection with a section of a load ring 2 on a telescopic pipe on a riser.
Figure 2b shows a simplified section of the invention comprising a cylinder arranged for connecting the wire to the load ring on the riser, and a gripping lever for taking care of used paid-out wire.
Figures 3a and 3b show a section of the embodiment of the cylinder in the invention.
Figure 3c shows an embodiment of the invention wherein a cutting means for paid-out wire are located within the cylinder.
Figure 3d illustrates an embodiment of the invention wherein a wedging means are made of a shape memory metal or an alloy having this property (SMA) .
Description of preferred embodiment of the invention
Figure la shows a drilling platform with a riser 1 connected to an exhaust valve in a well in geologic formations in the sea bed.
Figure lb sketches scematically that the wire 10a, b, . . ,h is taken on to the cellar deck, the riser tensioner 7 and the supply reel 11.
Figure 2a describes a riser tensioner system comprising a riser tensioner 7 with a hydraulic cylinder/piston 71 , 73 with a tackle block system 74,75 arranged for carrying a riser 1 in wires 10a,b, . . ,h . The wires 10a,b, . . ,h are usually fastened to a load ring 2 near the top of the riser 1. Usually, at least one passive supply reel 11 with new wire 10a ' ,b ' , .. ,h ' are located n the cellar deck in continuation of the wires 10a,b, . . , . Figure 2b shows in a simplified form an embodiment of the invention comprising a cylinder 8 which connects the wire 10a,b, . . ,h to the load ring 2.
Figure 3a shows some of the components being comprised of an embodiment of the invention. A tubular cylinder 8 is arranged for being run through by the wire 10a, b, . . ,h . One end of the cylinder 8 has a fastening boss 80 which is attached to the load ring 2. In a preferred embodiment of the invention, one cylinder for each wire 10a,J,..,h to retain the riser 1 is arranged, usually six to eight wires 10a,b, . . ,h . The cylinder 8 comprises a releasable and shiftable wedging means 9 with wire wedges 9 ' and lock ring 9" for retaining of the wire 10a,b, . . ,h . A wedge slider 14 is arranged for shifting the wedging means 9 with the wire 10a,b, . . ,h from a starting position furthest away from the load ring 2. The wedge slider 14 shifts the wedging means 9 in the direction towards the load ring 2 when the wire wedges 9 ' have got a grip about the wire 10a. Thus one (used/worn) end of the wire 10a, b, . . ,h is paid out near the load ring 2. The wedging means 9 is then shifted by the wedge slider 14 in the opposite direction of the load ring 2 back to the starting position. Thus, the wedging means 9 is in position for a new gripping and retaining of the wire 10a, b, .. ,h .
In one embodiment, at least part of the wedging means 9 , e.g. the wire wedge 9 ' , be made of a shape memory metal or an alloy having this property (SMA) . Such metals and alloys have the feature that after deformation, they have the ability to "remember" and retrieve their initial shape through heating. For ordinary metals an alloys, the deformation should not exceed a fraction of one percent before the deformation becomes plastic, that is, irreversible. With SMA the limit for plastic deformation is substantially increased if the strain of the body is below 10% and takes place below a certain temperature. The wire wedge 9' may for example have the shape of a cylinder. The cylinder expands or shrinks about the wire at temperatures as mentioned above. This embodiment of the invention is illustrated in figure 3d.
Locking pawls 18 located in the cylinder 8 are arranged for unidirectionally being run through by the wire and temporary retaining of the wire 10a,Jb,..,2ι while the wedging means 9 is shifted back to the starting position. Figur 3b shows how hydraulic pressure may be used for activating the wire wedges vaierkilene 9 ' and lock ring 5", together with the wedge slider 14 and, if any, the locking pawls 18 . In one embodiment the locking pawls 18 are merely spring-loaded and tow against the wire in one direction, and is tightened against the wire if the wire is pulled in the opposite direction.
Figur 3c shows how the used part of the wire 10a,b, . . ,h may be paid out through a channel running from the centre of the cylinder out on the side through the cylinder wall. Thus, the fastening boss 80 may be arranged rectilinerarly on the end of the cylinder so that no buckling bending moment arise on the wire 10a and on the cylinder 8.
In one embodiment, a hydraulically driven wire cutter 16 is arranged within the cylinder 8. This wire cutter is arranged for cuttin off the paid-out end of the used wire 10a,b, . . ,h by means of a hydraulic piston urging a wedge- shaped cutting edge 17 through the wire 10a.
In a preferred alternative embodiment of the invention, a separate, movable lever 20 with a retainer 22 arranged for gripping and retaining the paid-out wire 10a, b, . . ,h . This is required in order to take care of the cut wire 10a,J,..,h to prevent falling wire cutting against the riser and the exhaust valve (large dimensions of the wire are here in question) . Furthermore, it is not desired to have cut wire lying around the drilling location, wether on account of future well operations or of the environment as such. The lever 20 may also be provided with the wire cutter 16 , arranged for controlling the wire cutter 16 to engagement with the paid-out end of the paid-out wire 10a, b, .. ,h and cutting off a part of the paid-out end of the paid-out wire 10a, b, . . ,h . Arranging the wire cutter 16 on the lever 20 yields a reduction in material requirement as the wire cutter 16 is not required to be built into each single cylinder.
Supply and changing of a wire
According to an embodiment of the invention, changing of wire 10a,Jb,..,h takes place mechanically. This takes place in the following manner: a) A riser tensioner is taken out of normal operation.
The pressure in cylinder 73 of the riser tensioner is reduced so as to release the tension in a wire (e.g.
10a of the wires 10a, b, . . ,h . b) Clamp 76 is released from the wire 10a. c) Wedging means 9 with wire wedges 5' in position I is locked about the wire 10a by means of lock ring 5" . A wedge slider 14 shifts the wedging means 9 including the wire 10a from position I to position II closer to the load ring 2. One (used/worn) end of the wire 10a is paid out from the cylinder 8 . Wedge slider 14 shifts the wedging means 9 in the opposite direction from position II closer to the load ring 2 back to the starting position I for a new retaining of the wire 10a. Locking pawls 18 retain the wire 10a while the wedging means 9 is shifted back to the starting positon I. Through this operation, new wire 10a' is drawn from the supply reel 11 . This step is repeated until the desired length of wire 10a is replaced by new wire 10a' . d) Clamp 76 is again attached to a new position on the wire 10a, thereby dividing between the active part of the wire 10a in the riser tensioner, and the remaining length of wire 10b on the supply reel 11. e) Wire wedges 9 ' are locked about the wire 10a in position I by means of the lock ring 9 " . f) The pressure in the cylinder 73 of the riser tensioner is increased until the new portion of the wire between the clamp 76 and ring 21 is tensioned. g) Riser tensioner 7 is returned to a state of normal operation. h) The steps a-g are repeated for each wire (10a,b, . . ,h ) to be replaced or shifted, usually all.
In a preferred embodiment of the invention, hydraulically driven components will be present in the cylinder 8 and the surrounding components, but an embodiment of the invention with electrical components is also possible. As all components are hydraulically driven, the system may be operated by an operator in some distance, thereby substancially reducing the danger of injuries to the operator while at the same time the operation may be carried out more quickly and safely.

Claims

P a t e n t k r a v
1. Riser tensioner system comprising a riser tensioner (7) with a hydraulic cylinder/piston (71) including a tackle block system (73,75) arranged to carry a riser (1) in wires (10a,b,..,h) which usually are fastened to a load ring (2) at the top of the riser (1) , and at least one passive supply reel (11) with new wires (10a1 ,b' , .. ,h' ) in continuation of the wires (10a,b, .. ,h) , c h a r a c t e r i z e d in a cylinder (8) arranged for being run through of a wire (10a,b, .. ,h) , where one end of the cylinder has a fastening boss (80) attached to the load ring (2) and where the cylinder (8) comprises a releasable and shiftable wedging means (9) with wire wedges (9') and lock rings (9") for retaining the wire (10a, b, .. ,h) , a wedge slider (14) being firstly arranged for shifting the wedging means (9) including the wire (10a,b, .. ,h) from a starting point, towards the direction of the load ring (2) , arranged for paying out one (used/worn) end of the wire (10a, b, .. ,h) , and secondly arranged for shifting the wedging means (9) in the opposite direction from the load ring (2) back to the starting position for a new retaining of the wire (10a, b, .. ,h) , locking pawls (18) arranged for temporary retaining of the wire (10a ,b , .. ,h) while the wedging means (9) is shifted back to the starting positon, and a wire cutter (16) in the cylinder (8) arranged for cutting off the paid-out end of the used wire (10a ,b , .. ,h) .
2. Riser tensioner system according to claim 1, c h a r a c t e r i z e d in a separate, preferably hydraulically driven, movable lever (20) holding a wire cutter (16) , arranged for controlling the wire cutter (16) to engagement with the paid-out end of the paid-out wire (10a, b, .. ,h) and for cutting off the paid- out wire (10a ,b , .. ,h) .
3. Riser tensioner system according to claim 2, c h a r a c t e r i z e d in a hydraulically driven retainer (22) arranged for gripping and retaining the paid-out wire (10a,b, .. ,h) .
4. Riser tensioner system according to claim 1 or 2, c h a r a c t e r i z e d in a hydraulically driven wedge-shaped wire cutter (16) in the cylinder (8) arranged for moving along grooves across the channel of the wire through the cylinder (8) for cutting off the paid-out end of the used wire (10a, b, .. ,h) having passed the wire cutter (16) .
5. Riser tensioner system according to one of the preceding claims, c h a r a c t e r i z e d in that at least part of the wedging means (9) is made of a shape memory metal or an alloy of metals having this property (SMA) .
6. Method for paying out, cutting and changing wire on risers, c h a r a c t e r i z e d in that a) a riser tensioner is taken out of normal operational mode; the pressure in cylinder (73) of the riser tensioner is reduced so as to release the tension in a wire (e.g. 10a) of the wires (10a, b, .. ,h ) ; b) clamp (76) is released from the wire (10a) ; c) wedging means (9) with wire wedges (9') in position I is locked about the wire (10a) by means of lock ring (5") ,- a wedge slider (14) shifts the wedging means (9) with the wire (10a) from position I to position II closer to the load ring; one (used / worn) end of the wire (10a) , is paid out of the cylinder (8); the wedge slider (14) shifts the wedging means (9) in the opposite direction from position II closer to the load ring (2) back to the starting position I, for positioning for a new retaining of the wire (10a) ; locking pawls (18 ) retain the wire (10a) while the wedging means (9) is shifted back to the starting position I; at this operation, new wire (10a') is drawn from the supply reel (11) ; this step is repeated until the desired length of wire (10a) is replaced by new wire (10a1) ; d) clamp ( 76) is again attached to a new position on the wire (10a) , thereby dividing between the active part of the wire (10a) in the riser tensioner, and the remaining length of wire (10b) on the supply reel (11 ) ; e) wire wedges (5') are locked about the wire (10a) in position I by means of the lock ring (S"); f) the wire cutter (14 ) is activated and cuts the current wire (10a,b, . . ,h) ; g) the pressure in the cylinder ( 73 ) of the riser tensioner is increased until the new portion of the wire between the clamp ( 76) and ring (21 ) is tensioned; h) riser tensioner ( 7) is returned to a state of normal operation; i) the steps a-g are repeated for each wire (10a,b, . . ,h) to be replaced or shifted, usually all.
PCT/NO1999/000349 1998-11-18 1999-11-18 Supply system and method for changing wires in a riser tensioner system WO2000032903A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU14177/00A AU1417700A (en) 1998-11-18 1999-11-18 Supply system and method for changing wires in a riser tensioner system

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NO19985373 1998-11-18
NO19985373A NO310714B1 (en) 1998-11-18 1998-11-18 Feed system for a stretch line compensator

Publications (1)

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WO2000032903A1 true WO2000032903A1 (en) 2000-06-08

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NO (1) NO310714B1 (en)
WO (1) WO2000032903A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7037228B2 (en) * 2002-08-12 2006-05-02 Tsubakimoto Chain Co. Chain tension-imparting device

Citations (7)

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Publication number Priority date Publication date Assignee Title
US1610699A (en) * 1924-02-25 1926-12-14 Titusville Forge Company Rope knife
US4085509A (en) * 1976-04-07 1978-04-25 Martin-Decker Company Apparatus for compensating for the heaving of a floating drilling platform for connection with apparatus for measuring the rate of penetration of pipe run into an offshore well
US4098491A (en) * 1975-01-09 1978-07-04 Vetco Offshore Industries, Inc. Methods and apparatus for the control of a suspended weight from a floating vessel
EP0057622A2 (en) * 1981-01-19 1982-08-11 KLEY-FRANCE, Société Anonyme dite: Hydraulic linear winch comprising a pair of self-clamping jaws assuring alternatively the clamping of the axial cable carrying the load
DE3313199A1 (en) * 1983-04-12 1984-10-25 Fritz 5600 Wuppertal Stumpmeier CLAMP ASSEMBLY FOR A STEP-BY-STEP HYDRAULIC CABLE DEVICE
US4962817A (en) * 1989-04-03 1990-10-16 A.R.M. Design Development Active reference system
NO174170B (en) * 1985-06-14 1993-12-13 Inst Francais Du Petrole Cable cutting device

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1610699A (en) * 1924-02-25 1926-12-14 Titusville Forge Company Rope knife
US4098491A (en) * 1975-01-09 1978-07-04 Vetco Offshore Industries, Inc. Methods and apparatus for the control of a suspended weight from a floating vessel
US4085509A (en) * 1976-04-07 1978-04-25 Martin-Decker Company Apparatus for compensating for the heaving of a floating drilling platform for connection with apparatus for measuring the rate of penetration of pipe run into an offshore well
EP0057622A2 (en) * 1981-01-19 1982-08-11 KLEY-FRANCE, Société Anonyme dite: Hydraulic linear winch comprising a pair of self-clamping jaws assuring alternatively the clamping of the axial cable carrying the load
DE3313199A1 (en) * 1983-04-12 1984-10-25 Fritz 5600 Wuppertal Stumpmeier CLAMP ASSEMBLY FOR A STEP-BY-STEP HYDRAULIC CABLE DEVICE
NO174170B (en) * 1985-06-14 1993-12-13 Inst Francais Du Petrole Cable cutting device
US4962817A (en) * 1989-04-03 1990-10-16 A.R.M. Design Development Active reference system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7037228B2 (en) * 2002-08-12 2006-05-02 Tsubakimoto Chain Co. Chain tension-imparting device

Also Published As

Publication number Publication date
NO985373D0 (en) 1998-11-18
NO985373L (en) 2000-05-19
NO310714B1 (en) 2001-08-20
AU1417700A (en) 2000-06-19

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